Real-world use of cladribine tablets (completion rates and treatment persistence) in patients with multiple sclerosis in England: The CLARENCE study

Treatment with cladribine tablets, a high-efficacy disease-modifying therapy (DMT), has been available in England since 2017 for patients with highly active relapsing multiple sclerosis (MS). Real-world data on treatment completion, persistence and switching in patients treated with cladribine tablets are beginning to emerge, but only small single and multicentre cohorts have reported so far. This longitudinal retrospective observational study (CLARENCE) evaluated a large cohort (>1900) of patients with highly active relapsing MS, receiving cladribine tablets across England, to determine rates of treatment completion, persistence and switching in the real world.Using data obtained from Blueteq® forms, a compulsory requirement for DMT reimbursement in England, we evaluated rates of treatment completion (defined as the proportion of patients who received the full 2-year course of cladribine tablets), treatment persistence (defined as the proportion of patients who did not switch and/or discontinue treatment before receiving the full 2-year course) and treatment switch (defined as the proportion of patients who switched treatment from cladribine tablets to another DMT at any point after their first course). The change in Expanded Disability Status Scale (EDSS) score between Years 1 and 2 of treatment was also determined. All data were analysed descriptively.Blueteq® forms were completed for 1934 MS patients treated with cladribine tablets; of these patients, 691 (36%) were treatment naïve. The median EDSS score (range) at treatment initiation with cladribine tablets was 2.5 (0, 8.5). At time of analysis (September 2021, last follow-up point), a total of 1020 (53%) patients had completed the full 2-year course of cladribine tablets. At the same time point, 1762 (91%) patients were considered as treatment persistent (i.e., the patient had completed either 1 course of tablets with <18 months of follow-up data or the full 2-year course of cladribine tablets). Overall, 78 (4%) patients switched to another DMT at any point after their first course, which included 33 (1.7%) patients who switched after completing the full 2-year course. In terms of their disability, 469 (84%) patients had stable EDSS scores between Years 1 and 2 of treatment.In this large real-world study of patients receiving cladribine tablets across England, high rates of treatment persistence and low rates of switching were observed, with only 1.7% of patients receiving the full 2-year course and switching treatment. The majority (84%) of evaluable patients showed stable disability between Years 1 and 2 of treatment. These findings complement earlier data from clinical trials and real-world studies, confirming the effectiveness of cladribine tablets for patients with highly active relapsing MS.